9: Weathering, Sediment, and Soil
- Page ID
- 29106
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)- Explain why rocks formed at depth in the crust are susceptible to weathering at the surface.
- Describe the main processes of mechanical weathering, and the materials that are produced.
- Describe the main processes of chemical weathering, and common chemical weathering products.
- Explain the characteristics used to describe sediments, and what those characteristics can tell us about the origins of the sediments.
- Discuss the relationships between weathering and soil formation, and the origins of soil horizons.
- Describe and explain the distribution of North American soil types.
- Explain how changing weathering rates affect the carbon cycle and the climate system.
- 9.1: Physical Weathering
- This page discusses the formation of intrusive igneous and metamorphic rocks at great depths and the burial of sedimentary rocks under other sediments. It explains that weathering begins when these rocks are exposed at the surface and categorizes physical weathering into expansion and wedging types. It highlights frost, salt wedging, and the role of plant roots and animal activity in mechanical weathering.
- 9.2: Chemical Weathering
- This page covers the processes and impacts of chemical weathering, including dissolution, hydrolysis, hydration, and oxidation, which alter minerals and can contribute to environmental issues like acid rock drainage (ARD). Acidic runoff from ARD sites harms aquatic life by dissolving toxic metals. The example of the Mt. Washington Mine illustrates the adverse effects on salmon, though remediation has improved water quality.
- 9.3: Controls on Weathering Processes and Rates
- This page discusses the variability of weathering in different environments, impacted by climate, water, temperature, and minerals. It highlights the role of water in both chemical and physical weathering, with temperature enhancing reactions. Oxygen and carbon dioxide levels affect rates, particularly in soils.
- 9.4: Weathering and Erosion Produce Sediments
- This page explains the processes of weathering and erosion that create sediment composed of clasts of various sizes. The characteristics of these clasts, such as composition, grain size, sorting, rounding, and sphericity, reveal their geological history and deposition conditions. Quartz is highlighted for its resistance to weathering, while other minerals break down into smaller particles.
- 9.5: Weathering and Soil Formation
- This page highlights the vital role of weathering and soil formation in supporting life on Earth. It defines soil as a mixture of minerals and organic matter, influenced by factors like climate and parent material. Soil horizons form distinct layers through nutrient movement, while human activities such as deforestation and agriculture exacerbate soil erosion, disturbing the balance of soil formation and loss.
- 9.6: Soils of Canada
- This page discusses the evolution of Canada's soil classification system from the U.S. model to the Canadian Soil Classification System established in 1955. It identifies 10 soil orders adapted to Canada's climates, such as Podzolic and Chernozemic. The page highlights how soil formation processes differ by climate, including podzolization in cooler areas, and describes the development of organic soils and cryosols.
- 9.7: Weathering and Climate Change
- This page discusses the alarming rates of carbon dioxide being added to the atmosphere, surpassing levels observed during past climate extremes. It explains the rapid biological cycling of carbon versus the slow geological processes, particularly the weathering of minerals that helps store carbon long-term. Historical incidents illustrate the significance of the carbon cycle in maintaining climate stability.
- 9.8: Chapter 9 Summary and Key Term Check
- This page delves into Chapter 8, which covers weathering processes, including physical and chemical weathering, and their influence on rock and soil formation. It examines factors affecting weathering rates and the resulting sediments. The chapter also discusses soil formation, particularly in Canada, while linking weathering to the carbon cycle and its geological implications in the context of climate change.